U.S. patent application number 11/219891 was filed with the patent office on 2006-01-05 for mobile communication terminal capable of displaying communication mode.
This patent application is currently assigned to Kabushiki Kaisha Toshiba. Invention is credited to Kiyoshi Hattori.
Application Number | 20060003801 11/219891 |
Document ID | / |
Family ID | 19188130 |
Filed Date | 2006-01-05 |
United States Patent
Application |
20060003801 |
Kind Code |
A1 |
Hattori; Kiyoshi |
January 5, 2006 |
Mobile communication terminal capable of displaying communication
mode
Abstract
In a mobile communication terminal connectable to a first base
station using a first communication mode and a second base station
using a second communication mode that is different from the first
communication mode, a control message coming from an acquired one
of the first and second base stations is received. Based on the
received control message, the communication mode used in the base
station is recognized, and information indicative of the recognized
communication mode is informed to the user.
Inventors: |
Hattori; Kiyoshi; (Hino-shi,
JP) |
Correspondence
Address: |
BANNER & WITCOFF, LTD., ATTORNEYS FOR RESERVE;CLIENT NO. 4
1001 G STREET, N.W., 11TH FLOOR
WASHINGTON
DC
20001-4597
US
|
Assignee: |
Kabushiki Kaisha Toshiba
Tokyo
JP
|
Family ID: |
19188130 |
Appl. No.: |
11/219891 |
Filed: |
September 7, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10323838 |
Dec 20, 2002 |
|
|
|
11219891 |
Sep 7, 2005 |
|
|
|
Current U.S.
Class: |
455/552.1 ;
455/403 |
Current CPC
Class: |
H04M 1/724 20210101;
H04W 48/16 20130101; H04B 1/401 20130101 |
Class at
Publication: |
455/552.1 ;
455/403 |
International
Class: |
H04Q 7/20 20060101
H04Q007/20; H04M 1/00 20060101 H04M001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 2001 |
JP |
2001-388281 |
Claims
1. A mobile communication terminal connectable to a base station
comprising: means for acquiring a base station; means for receiving
a control message sent from the base station acquired by the
acquiring means; means for recognizing whether the communication
mode in use at the acquired base station is one of a first
communication mode and a second communication mode based on the
received control message, wherein the second communication mode is
upgraded from the first communication mode; and means for
indicating the recognized communication mode.
2. The terminal according to claim 1, wherein the acquiring means
acquires the base station when the mobile communication terminal is
turned on; and the recognizing means recognizes the communication
mode in use at the base station.
3. The terminal according to claim 1, wherein the acquired base
station is adapted to use both the first communication mode and the
second communication mode.
4. In a mobile communication network including base stations
configured to operate according to a first communication standard
and base stations configured to operate according to a second
communication standard different from the first communication
standard, a mobile communication terminal configured to be
connected to a base station, the mobile communication terminal
comprising: means for acquiring a base station; means for receiving
a control message sent from the acquired base station; means for
recognizing whether the acquired base station is assigned to
operate with the mobile communication terminal according to the
first communication standard or the second communication standard
based on the received control message; and means for indicating the
recognized communication standard by which the acquired base
station is configured to operate with the mobile communication
terminal.
5. The mobile communication terminal according to claim 4, wherein
the second communication standard is upgraded from the first
communication standard.
6. The mobile communication terminal according to claim 4, wherein
the acquired base station is configured to operate according to
both the first communication standard and the second communication
standard.
7. The mobile communication terminal according to claim 4, wherein
the acquiring means acquires the base station responsive to the
mobile communication terminal being turned on.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 10/323,838, filed Dec. 20, 2002, which is based upon and claims
the benefit of priority from the prior Japanese Patent Application
No. 2001-388281, filed Dec. 20, 2001, the entire contents of which
are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a mobile communication
terminal capable of being connected to a plurality of kinds of base
stations that use different communication modes.
[0004] 2. Description of the Related Art
[0005] In general, a mobile communication system includes a
plurality of base stations which are distributed over the service
area. A mobile communication terminal selects one of the base
stations, which has the best condition for communication and
acquires the selected base station. Thereby, radio communication is
enabled.
[0006] In the mobile communication system, there may be a case
where a part of the standards of the communication mode is upgraded
while the system is being in operation. For example, in mobile
communication systems using CDMA (Code Division Multiple Access), a
preparation is now progressing to upgrade IS95A/IS95B standards to
IS2000-1X standards designed to increase a data communication
speed, while basic portions of the IS95A/IS95B standards remain
unchanged.
[0007] It is not possible, however, to upgrade the standards of the
communication mode for all the base stations of the system at the
same time. In general, the standards are upgraded step by step.
Consequently, base stations with different standards are mixedly
present in the service area until completion of the work for
upgrading the standards for all base stations.
[0008] If a mobile communication terminal corresponding to both old
and new standards is to start information communication in this
state, it is uncertain whether the terminal is connected to a base
station with new standards or a base station with old standards,
depending on the conditions for communication, such as the current
location of the terminal or the condition of radio waves. For
example, if the mobile communication terminal of a use who wishes
high-speed data communication is connected to a base station with
old standards, a longer time than expected may be consumed until
completion of data communication, or a high communication charge
may occur. This is very disadvantageous.
BRIEF SUMMARY OF THE INVENTION
[0009] The object of the present invention is to provide a mobile
communication terminal that enables a user to confirm in advance a
usable communication mode at the time of starting information
communication, thereby preventing undesired information
communication from being performed.
[0010] According to an aspect of the present invention, there is
provided a mobile communication terminal connectable to a first
base station using a first communication mode and a second base
station using a second communication mode that is partly upgraded
from the first communication mode. The terminal includes
acquisition means for acquiring one of the first and second base
stations and indication means for indicating the communication
mode. The communication mode used in the base station is recognized
from a control message coming from the base station acquired by the
acquisition means. Information representative of the recognized
communication mode is informed to the user of the mobile
communication terminal.
[0011] Additional objects and advantages of the invention will be
set forth in the description which follows, and in part will be
obvious from the description, or may be learned by practice of the
invention. The objects and advantages of the invention may be
realized and obtained by means of the instrumentalities and
combinations particularly pointed out hereinafter.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0012] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate presently
preferred embodiments of the invention, and together with the
general description given above and the detailed description of the
preferred embodiments given below, serve to explain the principles
of the invention.
[0013] FIG. 1 schematically shows the structure of a mobile
communication system according to an embodiment of the present
invention;
[0014] FIG. 2 is a block diagram showing the structure of a mobile
communication terminal according to an embodiment of the
invention;
[0015] FIG. 3 shows a control sequence illustrating the procedures
and contents of a communication mode display control which is
performed in the mobile communication terminal shown in FIG. 2,
when power is turned on or when an idle handoff is executed in a
standby state;
[0016] FIG. 4 shows an example of a format of system parameter
messages used in the communication mode display control shown in
FIG. 3;
[0017] FIG. 5 shows control sequences illustrating the procedures
and contents of a communication mode display control which is
performed in the mobile communication terminal shown in FIG. 2,
when a handoff is executed during information communication;
[0018] FIG. 6 shows an example of a format of handoff direction
messages used in the communication mode display control illustrated
in FIG. 5;
[0019] FIG. 7 shows an example of a first display image of a
communication mode according to the communication mode display
control shown in FIGS. 3 and 5; and
[0020] FIG. 8 shows an example of a second display image of a
communication mode according to the communication mode display
control shown in FIGS. 3 and 5.
DETAILED DESCRIPTION OF THE INVENTION
[0021] An embodiment of a mobile communication terminal according
to the present invention will now be described with reference to
the accompanying drawings.
[0022] FIG. 1 schematically shows the structure of a mobile
communication system adopting a CDMA (Code Division Multiple
Access) method according to an embodiment of the invention.
[0023] A plurality of base stations BS1, BS2, . . . , are
distributed in a service area covered by the mobile communication
system. The base stations BS1, BS2, . . . , form radio
communication areas E1, E2, . . . , respectively, which are called
cells. A mobile communication terminal MS serving as a mobile
station is connected to the nearest base station via a radio
channel.
[0024] The base stations BS1, BS2, . . . , are classified into a
first base station group using a first communication mode, and a
second base station group using a second communication mode that
includes an upgraded part of the standard of the first
communication mode. For example, the first base station group uses
IS95A or IS95B which is a CDMA standard, and the second base
station group uses IS2000-1X that is formed by adding a high-speed
data transmission mode to the IS95A or IS95B standard.
[0025] The mobile communication terminal MS has functions
corresponding to both communication modes of IS95A or IS95B and
IS2000-1X. In addition, the mobile communication terminal MS has
functions corresponding to a personal mobile communication system
using CDMA, which is represented by PCS (Personal Communication
System), and to an analog mobile phone system using an analog
communication mode, which is represented by AMPS (Advanced Mobile
Phone System).
[0026] FIG. 2 is a block diagram showing the functional structures
of the mobile communication terminal MS.
[0027] In FIG. 2, a radio signal sent from the base station BS1,
BS2, . . . , is received by an antenna 1 and input to a reception
circuit (RX) 3 via a duplexer (DUP) 2. In the reception circuit 3,
the radio signal is mixed with a reception local oscillation signal
produced from a frequency synthesizer (SYN) 4 and is down-converted
to an intermediate frequency signal or a baseband signal. The
frequency of the reception local oscillation signal produced from
the frequency synthesizer 4 is instructed by a control signal SYC
from a control section 12.
[0028] The reception intermediate-frequency signal or reception
baseband signal is input to a CDMA signal processing section 6 when
the communication mode is set to be a digital mode using CDMA, or
to an analog audio circuit 19 when the communication mode is set to
be an analog mode.
[0029] The CDMA signal processing section 6 subjects the input
reception intermediate frequency signal or reception baseband
signal to a quadrature demodulation process and a despread spectrum
process using a spread code assigned to a reception channel.
Thereby, demodulated data corresponding to a data rate is obtained.
The demodulated data is input to a speech codec 7. Control data
indicative of a data rate, which is included in the demodulated
data, is input to the control section 12.
[0030] The speech codec 7 subjects the demodulation data output
from the CDMA signal processing section 6 to an expansion process
corresponding to the reception data rate informed from the control
section 12. In addition, the speech codec 7 subjects the expanded
data to a decoding process using Viterbi decoding, etc. and an
error correction decoding process, thereby reproducing baseband
reception digital data.
[0031] A PCM codec 8 performs different signal processing according
to a communication type (voice communication or data communication)
informed from the control section 12. Specifically, in the voice
communication mode, the PCM codec 8 performs PCM decoding of the
reception digital data output from the speech codec 7 and produces
an analog reception call signal. The analog reception call signal
is amplified by a reception call amplifier 9 and output from a
loudspeaker 10. On the other hand, in the data communication mode,
the reception digital data from the speech codec 7 is fed to the
control section 12. The control section 12 stores the reception
digital data in a storage section 13 and causes it to be displayed
on a display section 15.
[0032] The reception digital data, where necessary, may be
transferred to an external information terminal device (not shown)
such as a personal digital assistant (PDA) or a notebook personal
computer via an external interface (not shown).
[0033] On the other hand, the analog audio circuit 19
analog-demodulates the input reception intermediate frequency
signal through an FM detector and reproduces an analog reception
call signal. The analog reception call signal is amplified by the
reception call amplifier 9 and output from the loudspeaker 10.
[0034] An input voice of the speaker in the voice communication
mode is input through a microphone 11 as an analog transmission
call signal. The analog transmission call signal is amplified up to
a proper level by a transmission call amplifier 18. When the
digital mode is set as the communication mode, the amplified signal
is input to the PCM codec 8. When the analog mode is set as the
communication mode, the amplified signal is input to the analog
audio circuit 19.
[0035] The PCM codec 8 subjects the input analog transmission call
signal to a PCM encoding process. The transmission data thus
produced is supplied to the speech codec 7. In addition, data
produced from the external information terminal device is input to
the control section 12 via the external interface (not shown). The
data is then delivered from the control section 12 to the speech
codec 7 via the PCM codec 8.
[0036] In the voice communication mode, the speech codec 7 detects
an energy amount of the input voice on the basis of transmission
voice data produced from the PCM codec 8. Based on the detection
result, the speech codec 7 determines the data rate. The speech
codec 7 compresses the transmission data to a burst signal of a
format corresponding to the data rate, and subjects it to an error
correction encoding process. The speech codec 7 delivers the
resultant data to the CDMA signal processing section 6. On the
other hand, in the data communication mode, the speech codec 7
compresses the transmission data from the PCM codec 8 to a burst
signal of a format corresponding to a preset data rate and subjects
it to an error correction encoding process. The speed codec 7
delivers the resultant data to the CDMA signal processing section
6. The data rate in either the voice communication mode or data
communication mode is informed to the control section 12 as a
transmission data rate.
[0037] The CDMA signal processing section 6 subjects the burst
signal compressed by the speech codec 7 to a spread process using a
spread code assigned to the transmission channel. Then, the CDMA
signal processing section 6 subjects the spread-coded transmission
signal to a quadrature modulation process and delivers the
quadrature-modulated signal to a transmission circuit (TX) 5.
[0038] On the other hand, the analog audio circuit 19 modulates a
carrier signal by the input analog transmission call signal, using
an analog modulation method such as an FM modulation method. The
analog audio circuit 19 outputs the modulated carrier signal to the
transmission circuit (TX) 5.
[0039] The transmission circuit 5 mixes the input
quadrature-modulated signal or carrier signal with a transmission
local oscillation signal produced from the frequency synthesizer 4,
and converts the resultant signal to a radio frequency signal.
Based on the transmission data rate informed from the control
section 12, the transmission circuit 5 subjects only an effective
component of the radio frequency signal to radio frequency
amplification and outputs the RF amplified signal as a transmission
radio frequency signal. The transmission radio frequency signal
produced from the transmission circuit 5 is fed to the antenna 1
via the duplexer 2. The transmission radio frequency signal is then
burst-transmitted to the base station (not shown) from the antenna
1.
[0040] An input section 14 is provided with keys including a dial
key, a send key, a power key, an end key, a volume control key, and
a mode designating key. The display section 15 is provided with an
LCD display and an LED. The LCD display displays, for example,
information in a phone book, an incoming call and an outgoing call
history, a telephone number of a counter-part terminal, and an
operation state of this terminal. The LED is turned on or flickered
when an incoming call has been received or when a discharge state
of a battery 16 is indicated, that is, information demanding
recharging of the battery 16 is displayed.
[0041] Reference numeral 17 denotes a power supply circuit. Based
on an output from the battery 16, the power supply circuit 17
produces a predetermined power supply voltage Vcc and supplies it
to each circuit component. The power supply circuit 17 includes a
recharging circuit for recharging the battery 16.
[0042] The control section 12 includes, for example, a
microcomputer as a main control unit. In addition to conventional
control functions such as a radio communication control function
and a position register control function, the control section 12
has a base station acquisition control function 12a and a
communication mode display control function 12b as control
functions relating to the present invention. The radio
communication control function executes a radio channel connection
control in accordance with a incoming call and outgoing call, thus
enabling voice communication or data communication.
[0043] The base station acquisition control function 12a executes a
search for the base station BS1, BS2, . . . , when power is turned
on, when a idle handoff is effected in a standby state, when a
handoff is effected during information communication, or when
selection or re-selection of the system is effected. Based on the
search result, the base station that meets the condition for
communication is selected, and a process for acquiring the selected
base station is performed.
[0044] In the communication mode display control function 12b, a
control message is received from the base station acquired by the
base station acquisition control function 12a, and data indicative
of the communication mode is extracted from the received control
message. Based on the extracted data, display data for notifying
the user of the communication mode is produced and the produced
display data is displayed on the LCD display of the display section
15. A mark representative of the communication mode, for instance,
is used as the display data.
[0045] The base station acquisition control function 12a and
communication mode display control function 12b are realized by
causing the microprocessor of control section 12 to execute
programs. The programs are stored in a program memory in the
control section 12 or in a program storage area in the storage
section 13.
[0046] There are three methods of storing the programs in the
program memory or the program storage area: 1) to record programs
by means of a program writer at the time of manufacture or
assembly, 2) to read programs from an external memory such as a
CD-ROM or a memory card at the time of starting the operation of
the terminal and to write the read programs in the program memory
or the program storage area, and 3) to download programs from the
Web site of a communication service provider or a manufacturer via
a communication network, and to write the downloaded programs in
the program memory or program storage area.
[0047] The operation of the mobile communication terminal MS with
the above structure will now be described.
[0048] When power has been turned on or when a handoff is effected
in the standby state, the mobile communication terminal MS performs
the following communication mode display operation. FIG. 3 shows a
sequence illustrating the control procedures and control
contents.
[0049] When power has been turned on, the control section 12 of the
mobile communication terminal MS executes a base station search
process in step 3a. In the base station search process, the
terminal MS successively receives pilot signals transmitted from
neighboring base stations and measures the quality of reception of
the pilot signals. Based on a measured result of the quality of
reception, the best base station to be acquired is selected.
[0050] Assume that the mobile communication terminal MS is located
at a boarder area between the radio area E2 and radio area E5, as
shown in FIG. 1. Assume also that the quality of reception of the
pilot signal from the base station BS2 is higher than that of the
pilot signal from the base station B5. In this case, the control
section 12 of the mobile communication terminal MS receives a sync
channel signal sent from the selected base station BS2 and performs
a process for establishing sync with the base station BS2 on the
basis of the sync channel signal (step 3b). If sync is established,
the reception channel is switched to the paging channel, and the
control section 12 is set in the standby state (step 3d). At this
time, the control section 12 executes a process for displaying
information representing the communication mode in step 3c.
[0051] To be more specific, the control section 12 receives an
extended system parameters message (ESPM) sent from the base
station BS2 over the paging channel. FIG. 4 shows a format of the
ESPM. Data indicative of the communication mode used by the base
station BS2 is extracted from a P_REV field P1 of the received
ESPM. Based on the extracted data, a display mark of the
communication mode is generated. The generated display mark is
displayed on a PICT information display area 15a of the LCD display
provided in the display section 15.
[0052] If the communication mode of the base station BS2 is
IS2000-1X, data representative of IS2000-1X is put in the P REV
field P1 of the incoming ESPM from the base station BS2. Thus, the
PICT information display area 15a of LCD display displays mark "1X"
indicative of the IS2000-1X. In FIG. 7, numeral 4a denotes an
example of display.
[0053] The user can confirm the communication mode of the base
station BS2 acquired by the terminal, on the basis of the mark 4a
displayed on the PICT information display area 15a.
[0054] The control section 12 in the standby state 3d periodically
performs a base station search in step 3e. Based on the quality of
reception of the pilot signal from the neighboring base stations,
which is measured by the base station search, the control section
12 determines in step 3f whether an idle handoff is necessary or
not.
[0055] Assume that the mobile communication terminal MS has moved
closer to the base station BS5, as indicated by MS' in FIG. 1. In
this case, the quality of reception of the pilot signal from the
base station BS5 becomes higher than that of the pilot signal from
the base station BS2. The control section 12 thus determines that a
handoff is necessary and advances to step 3g. In step 3g, the
control section 12 receives a sync channel signal sent from the
base station BS5 and executes an operation for establishing sync
with the base station BS5 on the basis of the sync channel signal.
If sync is established, the reception channel is switched to the
paging channel, and the control section 12 is set in the standby
state 3i. At this time, the control section 12 executes a
communication mode display changing process in step 3h.
[0056] To be more specific, the control section 12 receives an ESPM
sent from the base station BS5 (i.e. a handoff destination) over
the paging channel, and extracts data representative of the
communication mode used by the base station BS5 (the handoff
destination) from the P_REV field P1 of the received ESPM. Based on
the extracted data, a display mark of the communication mode is
generated. The generated display mark is displayed on the PICT
information display area 15a of the LCD display.
[0057] If the communication mode of the base station BS5 of the
handoff destination is IS95A or 95B, data representative of IS95A
or 95B is put in the P_REV field P1 of the incoming ESPM from the
base station BS5. Thus, the PICT information display area 15a of
LCD display displays mark "D" indicative of the IS95A or 95B. In
FIG. 8, numeral 4b denotes an example of display.
[0058] The display of "1X" indicative of the communication mode of
the base station BS2 (i.e. a handoff origin) is kept until the
communication mode "D" of the base station BS5 of the handoff
destination is displayed. In short, the communication mode of the
base station BS2 of the handoff origin is displayed during the idle
handoff process.
[0059] The user can thus confirm the communication mode of the base
station BS5 acquired by the mobile communication terminal MS' even
after the idle handoff. Therefore, the user can confirm the
communication mode and performs the information communication of
the format suitable for the usable communication mode.
[0060] For example, when large-volume data communication is to be
performed as in a case of downloading image content or music
content from a Web page or a Web site, this data communication can
be performed when the IS 2000-1X standard with the high-speed data
transmission mode is usable.
[0061] A communication mode display control in the case where a
handoff is effected during the information communication will now
be described. FIG. 5 shows a sequence illustrating the control
procedures and control contents.
[0062] Assume that the mobile communication terminal MS is
performing radio communication with the base station BS2 according
to the IS2000-1X standard. At this time, the PICT information
display area 15a of the LCD display displays the mark "1X"
indicating that the communication mode in use is IS2000-1X.
[0063] In this communication state 5a, the control section 12
periodically performs a base station search in step 5b. Based on
the quality of reception of the pilot signal from the neighboring
base stations, which is measured by the base station search 5b, the
control section 12 determines in step 5c whether an idle handoff is
necessary or not.
[0064] Assume that the mobile communication terminal MS has moved
closer to the base station BS5, as indicated by MS' in FIG. 1. In
this case, the quality of reception of the pilot signal from the
base station BS5 becomes higher than that of the pilot signal from
the base station BS2. The control section 12 thus determines that a
handoff is necessary and executes the following handoff
process.
[0065] To start with, the control section 12 prepares a message
(PSMM: Pilot Strength Measurement Message) representative of the
quality of reception of the pilot signal from each of the
neighboring base stations, which has been measured by the base
station search 5b, and sends the PSMM to the base station BS2 which
is currently acquired. Upon receiving the PSMM, the base station
BS2 returns an acknowledge message (BSACK) for the PSMM to the
mobile communication terminal MS. Then, the base station BS2
prepares a message indicative of the handoff destination (EHDM
(Extended Handoff Direction Message) or GHDM (General Handoff
Direction Message) and sends the EHDM or GHDM to the mobile
communication terminal MS requesting the handoff.
[0066] Upon receiving the EHDM or GHDM, the control section 12 of
the mobile communication terminal MS executes a process for
establishing sync with the base station BS5 of the handoff
destination according to the EHDM or GHDM, while maintaining the
radio link with the base station BS2 that is currently acquired. If
sync is established and a radio link is established by the traffic
channel, the control section 12 prepares a handoff-completion
message (HOCM: Handoff Completion Message) and sends it to the base
station BS2 of the handoff origin. Thus, the mobile communication
terminal MS passes into a state 5d in which the terminal MS is
connected to both the base station BS2 of the handoff origin and
the base station BS5 of the handoff destination.
[0067] In this state, the control section 12 of mobile
communication terminal MS monitors the quality of reception of the
pilot signals from the base station BS2 of the handoff origin and
the base station BS5 of the handoff destination. If a difference in
quality between both pilot signals exceeds a threshold, the control
section 12 sends a PSMM to each of the base stations BS2 and BS5.
Upon receiving the PSMM, each of the base stations BS2 and BS5
returns an acknowledge message BSACK to the mobile communication
terminal MS of the handoff request origin. In addition, each of the
base stations BS2 and BS5 prepares an EHDM or GHDM and sends it to
the mobile communication terminal MS. FIG. 6 shows a format of the
EHDM.
[0068] Upon receiving the EHDM or GHDM from each of the base
stations BS2 and BS5, the control section 12 of the mobile
communication terminal MS releases the radio link with the base
station BS2 of the handoff origin according to the instruction of
the EHDM or GHDM. If this radio link release process is completed,
the mobile communication terminal MS prepares an HOCM and sends it
to each of the base station BS2 of the handoff origin and the base
station BS5 of the handoff destination. Thus, the mobile
communication terminal MS passes into a state 5g in which it is
connected to only the base station BS5 of the handoff
destination.
[0069] In step 5e of the handoff process, the control section 12 of
mobile communication terminal MS extracts data representative of
the communication mode used by the base station BS5 of the handoff
destination from the P_REV field P2 of the EHDM or GHDM sent from
the base station BS5 of the handoff destination. In step 5f, upon
confirming the reception of an acknowledge message BSACK from the
base station BS5 of the handoff destination in response to the
HOCM, the control section 12 generates a display mark of the
communication mode based on the data extracted from the P REV field
P2, and displays it on the PICT information display area 15a of the
LCD display.
[0070] For example, if the communication mode of the base station
BS5 of the handoff destination is IS95A or 95B, the PICT
information display area 15a of the LCD display displays mark "D"
indicative of the IS95A or 95B standard, as shown in FIG. 8 by
numeral 6b.
[0071] In the above handoff process, the display of "1X" indicative
of the communication mode of the base station BS2 of the handoff
origin is kept until the reception of the HDM from the base station
BS5 of the handoff destination and the completion of the handoff
process. In short, in the handoff process in the information
communication, too, the communication mode of the base station BS2
of the handoff origin is displayed until the completion of the
series of handoff process procedures.
[0072] Accordingly, even when the handoff is effected during the
information communication and consequently the communication mode
has changed, the use can also recognize the change of the
communication mode. For example, when the communication mode has
been changed from IS2000-1X to IS95A or 95B during large-volume
data communication, the user can return to the radio communication
area E2 of base station BS2 or finish the data communication in an
incomplete state.
[0073] As has been described above, according to the present
embodiment, the data representative of the communication mode is
extracted from the P_REV field P1, P2 of the ESPM, EHDM or GHDM
coming from the newly acquired base station, when the power is
turned on, when the idle handoff is performed in the standby state,
or when the handoff is effected in the information communication.
Based on the extracted data, the display mark indicative of the
communication mode used by the acquired base station is generated,
and the generated mark is displayed on the PICT information display
area 15a of the LCD display.
[0074] Accordingly, the user can always confirm the communication
mode of the base station acquired by his/her mobile communication
terminal MS, when the idle handoff is effected in the standby
state, or when the handoff is effected during the information
communication, as well as when the power is turned on. Therefore,
the user can confirm the displayed communication mode and select
the information communication of the format suitable for the usable
communication mode.
[0075] The present invention is not limited to the above-described
embodiment. For example, in the above embodiment, a handoff is
performed between a plurality of base stations belonging to one
mobile communication system. However, the communication mode
display control of the present invention can be applied to the case
where a so-called system selection is performed to switch the
system of connection destination among a plurality of mobile
communication systems. In this case, too, an incoming system
parameter message is received from a base station of a system which
has been newly selected by the system selection process. Data
representative of the communication mode is extracted from the
received message, and informed to the user. In this fashion, the
communication mode display control can similarly be realized.
[0076] In the above-described embodiment, when power has been
turned on, data representative of the communication mode is
extracted from the P_REV field set in the ESPM sent from the
acquired base station over the paging channel, and the extracted
data is displayed. Alternatively, data representative of the
communication mode may be extracted from the P_REV field set in the
sync channel message sent from the acquired base station, and the
extracted data is displayed.
[0077] In the above embodiment, a soft handoff has been described
as a handoff operation during information communication. However,
this invention is also applicable to a hard handoff including radio
frequency changes.
[0078] When the communication mode has been changed by the handoff
process, the display mark "1X" or "D" indicating the changed
communication mode may be flickered, or a display message
indicating the change of the communication mode may additionally be
generated and displayed. Moreover, the change of the communication
mode may be reported to the user by alerting sound or vibration.
Thereby, the user can clearly recognize the change of the
communication mode.
[0079] The communication mode indication means is not limited to
the displaying of the mark representative of the communication
mode. A display message indicating the communication mode may be
generated and displayed. In addition, a voice message indicating
the communication mode may be generated using speech synthesis
technology and output from a loudspeaker.
[0080] In the above embodiment, the mobile communication system
wherein a base station using IS95A/95B and a base station using
IS2000-1X are mixedly present has been described by way of example.
The invention is also applicable to systems wherein base stations
using other communication modes are mixedly present.
[0081] Means for designating and inputting a communication mode
desired by the user may be provided. It is determined whether the
communication mode of the acquired base station agrees with the
desired communication mode designated by the user. If the
communication modes do not coincide, a message to this effect,
together with information representative of the communication mode,
is informed to the user. Thereby, if a base station using the
communication mode desired by the user has not been acquired, the
user can clearly recognize this fact. The possibility of
communication being performed with an undesired communication mode
can further be reduced.
[0082] A function of accepting a base station re-acquisition
request and a base station re-acquisition control function may
further be provided. Assume that the user, who was notified of the
communication mode, has input a re-acquisition request for changing
the already acquired base station to a base station using the
desired communication mode. In this case, a search for neighboring
base stations is conducted once again according to the request.
Based on the search result, it is determined whether there is a
base station using the communication mode desired by the user. If
there is an acquirable base station among base stations using the
communication mode desired by the user, a process is executed to
change the acquired base station to this one. If there is no
acquirable base station among base stations using the communication
mode desired by the user, a message indicating the impossibility of
change of the base station and the reason therefor is generated and
informed to the user while the already acquired base station is
maintained.
[0083] With this structure, when a base station using the desired
communication mode is not acquired, the user can make the terminal
execute re-acquisition of the base station by a simple operation.
In addition, when a base station using the desired communication
mode cannot be acquired, the user can clearly recognize this fact
and the reason. Accordingly, the user can clearly know the reason
why the desired communication mode cannot be used, and the user can
take an appropriate measure, for example, by moving into a radio
area of some other base station.
[0084] In the above embodiment, in the idle handoff effected in the
standby state, the communication mode is displayed on the basis of
the paging signal first sent from the base station with which the
terminal has been synchronized. Then, the terminal is set in the
standby state. Alternatively, after the terminal passes in the
standby state, paging signals that are periodically sent from base
stations may be received to detect the P-REV value. The just
detected value and the previously received value are compared, and
the display of the communication mode may be updated if there is
change or addition.
[0085] The kinds of communication modes, the kinds and structures
of the mobile communication terminal, the communication mode
indication control procedure and the contents thereof, the content
of indication information (e.g. including information
representative of a changed or added function), the kinds and
structure of indication means, etc., may be modified without
departing from the spirit of the present invention.
[0086] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
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